[cdi-dev] [JBoss JIRA] (CDI-628) Allow overriding of Scope at Injection Point

[Romain Manni-Bucau (JIRA)]

    [ https://issues.jboss.org/browse/CDI-628?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13290334#comment-13290334 ] 

Romain Manni-Bucau commented on CDI-628:
----------------------------------------

Looks like breaking CDI concept to me (loose coupling since you need to know what you inject handling the scope at that level) and already doable through an extension so not sure it should be a core feature or a feature flipping library

> Allow overriding of Scope at Injection Point
> --------------------------------------------
>
>                 Key: CDI-628
>                 URL: https://issues.jboss.org/browse/CDI-628
>             Project: CDI Specification Issues
>          Issue Type: Feature Request
>    Affects Versions: 2.0 (proposed)
>            Reporter: Stephan Knitelius
>            Priority: Minor
>
> Allow overriding scopes at injection point.
> {code}
> @SessionScope
> public class FeatureState {...}
> public class Bean B {
>   @Inject
>   @ConversationScoped //Overriding original scope
>   public BeanA beanA;
>   ...
> }
> {code}
> Sample use-case for for a feature flag:
> {code}
> @Alternative
> public class FeatureStateProducer {
>   @Inject
>   @SessionScoped
>   private FeatureState devState;
>   @Inject
>   @ConversationScoped
>   private FeatureState viewState;
>   @Inject
>   private JNDIProvider jndiProvider;
>   private boolean viewOnly = true;
>   @PostConstruct
>   public void postConstruct() {
>     this.viewMode = ...; //read config.
>   }
>   @Produces
>   public FeatureState produce() {
>     return viewOnly ? viewState : devState;
>   }
> }
> {code}
> Currently this can be solved by overriding scope with @Qualifiers:
> {code}
> @ViewMode
> @ConversationScoped
> public class ViewFeatureState extends FeatureState {...}
> @DevMode
> @SessionScoped
> public class DevFeatureState extends FeatureState {...}
> {code}
> Risks:
> * developers might start to define the scopes at IP and on bean (hard to maintain).
> * confusing when debugging, annotation on bean, e.g. @ApplicationScoped yet behaving differently.
> * etc... 



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